• Title/Summary/Keyword: compiler

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Design of Translator for generating Secure Java Bytecode from Thread code of Multithreaded Models (다중스레드 모델의 스레드 코드를 안전한 자바 바이트코드로 변환하기 위한 번역기 설계)

  • 김기태;유원희
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2002.06a
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    • pp.148-155
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    • 2002
  • Multithreaded models improve the efficiency of parallel systems by combining inner parallelism, asynchronous data availability and the locality of von Neumann model. This model executes thread code which is generated by compiler and of which quality is given by the method of generation. But multithreaded models have the demerit that execution model is restricted to a specific platform. On the contrary, Java has the platform independency, so if we can translate from threads code to Java bytecode, we can use the advantages of multithreaded models in many platforms. Java executes Java bytecode which is intermediate language format for Java virtual machine. Java bytecode plays a role of an intermediate language in translator and Java virtual machine work as back-end in translator. But, Java bytecode which is translated from multithreaded models have the demerit that it is not secure. This paper, multhithread code whose feature of platform independent can execute in java virtual machine. We design and implement translator which translate from thread code of multithreaded code to Java bytecode and which check secure problems from Java bytecode.

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Yongdoseo(龍圖墅) and Guimunwon(龜文園) which Applied a Sangsu(象數) Principle on Garden Composition (상수(象數) 원리를 정원구성에 적용한 용도서(龍圖墅)와 귀문원(龜文園))

  • Hong, Hyoung-Soon
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.2
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    • pp.119-129
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    • 2012
  • Yongdoseo and Guimunwon are described in "Bokgeo(卜居, fixabode)" of "Sanlimkyengje(山林經濟)" written by Manseon Hong. This record is a unique garden conceptual idea applying the principles of Hetu(河圖) and Luoshu(洛書), fanciful gardens which have not been actually constructed. Here, two garden types were concretely described respectively, however the underlying meaning therein cannot be apprehended without exact understanding about Sangsu studies. Therefore, the purpose of this study is to illuminate the meaning contained in Garden illustration and the historical meaning of landscape therein through considering this text. To achieve the purpose of this study, the writer and the compiler who are the background of this writing and the outline of Sangsu studies were investigated. Also, the principles of Saengsu(生數), Seongsu(成數), Yin Yang(陰陽), Four Bodies(四象), Palgwedo(八卦圖), etc. which are in Hetu and Luoshu were considered. The result of this study went through this research process is summarized as follows. First, Hetu Luoshu are conceptual definitions which wholly abstracted the basic propositions of Sangsu philosophy such as the universe change principle, etc., while Yongdoseo and Guimunwon can be said to be operational definitions which apply those as garden composition principle, enabling to experience the meaning contained therein concretely and explain it in a replicable way. This attempt is a unique example, unprecedented in Chinaas well. Second, as a livingspace, garden was selected as a means to concretize operational definitions about the meaning of Hetu Luoshu, and as the property to reproduce the bearings concept, the location and the number, etc. of Hetu Luoshu, Taegukjeong(太極亭), Shipjagak(十字閣), Dondae(墩臺), well, pond as well as various kinds of trees were used. Third, the main motif of Yongdoseo and Guimunwon is the relation between Apriority(先天) and Posterior(後天), and the relation between Constitution(體) and Use(用) of Hetu and Luoshu respectively. That is, Yongdoseo planted evergreen trees such as Shipjangcheong(十長靑) in order to symbolize the universe creation principle which Hetu stands for, i.e. silent, harmonious, orderly and win-win image. In Guimunwon, flowering trees(花木) and fruit trees(果木) were planted freely to express the change of Posterior which Luoshu stands for, thatis, dynamic, disharmonious, disorderly, incompatible(相剋) and changing image. The effects intended to be attained through such planting were, 'freshness and cheerfulness(淸爽)' of Yongdoseo and 'splendidness' of Guimunwon respectively. Sangsu studies based on Hetu and Luoshu is a unique thinking system to the Orient which came from the accumulated wisdom of several scholars from various schools through a long period since ancient times. Therefore, the concept and the theory thereof are profound and huge, and its viewpoints of interpretation are diverse. It is a limit of this study that more in-depth and various consideration was not performed. As a further research project, more empirical study of Orientalism such as Sangsu studies, etc. inherent in Traditional Garden is necessary.

Improved Original Entry Point Detection Method Based on PinDemonium (PinDemonium 기반 Original Entry Point 탐지 방법 개선)

  • Kim, Gyeong Min;Park, Yong Su
    • KIPS Transactions on Computer and Communication Systems
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    • v.7 no.6
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    • pp.155-164
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    • 2018
  • Many malicious programs have been compressed or encrypted using various commercial packers to prevent reverse engineering, So malicious code analysts must decompress or decrypt them first. The OEP (Original Entry Point) is the address of the first instruction executed after returning the encrypted or compressed executable file back to the original binary state. Several unpackers, including PinDemonium, execute the packed file and keep tracks of the addresses until the OEP appears and find the OEP among the addresses. However, instead of finding exact one OEP, unpackers provide a relatively large set of OEP candidates and sometimes OEP is missing among candidates. In other words, existing unpackers have difficulty in finding the correct OEP. We have developed new tool which provides fewer OEP candidate sets by adding two methods based on the property of the OEP. In this paper, we propose two methods to provide fewer OEP candidate sets by using the property that the function call sequence and parameters are same between packed program and original program. First way is based on a function call. Programs written in the C/C++ language are compiled to translate languages into binary code. Compiler-specific system functions are added to the compiled program. After examining these functions, we have added a method that we suggest to PinDemonium to detect the unpacking work by matching the patterns of system functions that are called in packed programs and unpacked programs. Second way is based on parameters. The parameters include not only the user-entered inputs, but also the system inputs. We have added a method that we suggest to PinDemonium to find the OEP using the system parameters of a particular function in stack memory. OEP detection experiments were performed on sample programs packed by 16 commercial packers. We can reduce the OEP candidate by more than 40% on average compared to PinDemonium except 2 commercial packers which are can not be executed due to the anti-debugging technique.

The Integer Number Divider Using Improved Reciprocal Algorithm (개선된 역수 알고리즘을 사용한 정수 나눗셈기)

  • Song, Hong-Bok;Park, Chang-Soo;Cho, Gyeong-Yeon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.7
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    • pp.1218-1226
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    • 2008
  • With the development of semiconductor integrated technology and with the increasing use of multimedia functions in computer, more functions have been implemented as hardware. Nowadays, most microprocessors beyond 32 bits generally implement an integer multiplier as hardware. However, as for a divider, only specific microprocessor implements traditional SRT algorithm as hardware due to complexity of implementation and slow speed. This paper suggested an algorithm that uses a multiplier, 'w bit $\times$ w bit = 2w bit', to process $\frac{N}{D}$ integer division. That is, the reciprocal number D is first calculated, and then multiply dividend N to process integer division. In this paper, when the divisor D is '$D=0.d{\times}2^L$, 0.5 < 0.d < 1.0', approximate value of ' $\frac{1}{D}$', '$1.g{\times}2^{-L}$', which satisfies ' $0.d{\times}1.g=1+e$, $e<2^{-w}$', is defined as over reciprocal number and then an algorithm for over reciprocal number is suggested. This algorithm multiplies over reciprocal number '$01.g{\times}2^{-L}$' by dividend N to process $\frac{N}{D}$ integer division. The algorithm suggested in this paper doesn't require additional revision, because it can calculate correct reciprocal number. In addition, this algorithm uses only multiplier, so additional hardware for division is not required to implement microprocessor. Also, it shows faster speed than the conventional SRT algorithm and performs operation by word unit, accordingly it is more suitable to make compiler than the existing division algorithm. In conclusion, results from this study could be used widely for implementation SOC(System on Chip) and etc. which has been restricted to microprocessor and size of the hardware.

A Study on the Chinese Translated of Korean version Yeonhaengnok(燕行錄) of 『Sang-bong-lok』 in Korean (한역본(漢譯本) 연행록 『상봉록(桑蓬錄)』의 특징과 한역(漢譯) 양상 연구)

  • Chaung, Nae Won
    • (The)Study of the Eastern Classic
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    • no.55
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    • pp.147-172
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    • 2014
  • Kang Jae Eung translated "Sang-bong-lok" of Kang Ho Boo from Korean into Chinese. There is Yeonhaengnok(燕行錄) written in with Korean and Chinese among 500 Yeonhaengnok(燕行錄). Especially it is very rare that is translated from Korean into Chinese. Because of there aspect, it is valuable and worth studying. "Sang-bong-lok" was 3 series by origin, but now we have only 2 series. That is the original text written in Chinese by Kang Ho Boo, a Korean version by Kang Ho Boo, and Chinese translated of Korean version by his descindants Kang Jae Eung. Original text dosen't exists now undiscovered yet. Chinese version "Sang-bong-lok" is distinguished from the other Yeonhaengnok(燕行錄) and classical novel in form and contents. In formal aspect, Chinese version "Sang-bong-lok" describes an industry remarks in prologue. This industry remark describes standard and form of writing. Looking industry remark, you can find that Kang Jae Eung didn't add or subject the sentence of original text and distinguished between his own sentence and original text. This compiling system distinguishing compiler from original writter is rare enough to so that you cannot find it in other Yeonhaengnok(燕行錄). In contents, Kang Jae Eung almost transcribed Korean Yeonhaengnok(燕行錄) without subtraction and added special information to promote the view of Kang Ho Boo. After discription, Kang Jae Eung covered all information and reviewed it and added opinion to it. Kang Jae Eung's conclusion is sometimes same or different from Kang Ho Boo's. Anyway it is worthy of noticing that Kang Jae Eung wrote his opinion after Kang Ho Boo's sentence.